Vector synchronizes on each individual operation. That’s almost never what you want to do.
Generally you want to synchronize a whole sequence of operations. Synchronizing individual operations is both less safe (if you iterate over a
Vector, for instance, you still need to take out a lock to avoid anyone else changing the collection at the same time, which would cause a
ConcurrentModificationException in the iterating thread) but also slower (why take out a lock repeatedly when once will be enough)?
Of course, it also has the overhead of locking even when you don’t need to.
Basically, it’s a very flawed approach to synchronization in most situations. As Mr Brian Henk pointed out, you can decorate a collection using the calls such as
Collections.synchronizedList – the fact that
Vector combines both the “resized array” collection implementation with the “synchronize every operation” bit is another example of poor design; the decoration approach gives cleaner separation of concerns.
As for a
Stack equivalent – I’d look at
ArrayDeque to start with.